How long does it take for the dilating eyedrops to wear off?

Faster w/reversing. There are drops called reversing drops that many eye doctors use to speed up the recovery after dilation. Dapirazole hcl 0.5%is an eyedrop that helps the mydriacyl (tropicamide) to loosen its hold on the receptors in the iris muscles that lead to dilated pupils. Then the dilating drops can wear off in 45 minutes to an hour, in most cases.
Hours, usually. For most people, the nuisance symptoms of the dilating drops, namely the blurred near vision and sensitivity to light, are decreased or gone by a few hours, usually 4 to 6. For the uncommon person, however, it can take 24-48 hours for all the symptoms to completely wear off.
3 hours to 1 week. Depending on your sensitivity and the type and dosage of eyedrop, dilating eyedrops can take between 3 hrs and 1 week (maybe longer!) to wear off. You should let the doctor who dilated you know if it lasts more than 24 hrs, but it is not a medical emergency. It can be quite inconvenient, though.